GE公司注塑技術(shù)

GEPlasticsINJECTIONMOLDINGe注射模塑技術(shù)InjectionMoldingIntroduction注塑之優(yōu)點(diǎn)高生產(chǎn)率可大批量生產(chǎn)低人工成本易自動化最少的二次加工可生產(chǎn)很小制件最少報(bào)廢率可生產(chǎn)緊公差制件可注塑帶嵌件制品可加玻纖,碳纖等填充物可生產(chǎn)復(fù)雜制件可有好的裝飾InjectionMoldingIntroductionGOODPARTMaterial材料Tooling模具Processing工藝Design設(shè)計(jì)好產(chǎn)品Equipment設(shè)備InjectionMoldingEquipmentMACHINESHOTSIZE機(jī)器注射容量PartWeight=40-80%ofMachineShotSize制件重量=40-80%機(jī)器注射容量OptimalPartWeight=40~60%ofMachineShotSize制件重量=40-60%機(jī)器注射容量InjectionMoldingEquipmentInjectionMoldingEquipmentScrewTypeMachinesAreRecommended推薦采用的螺桿類型UniformPlasticizing

均勻塑化LessPressureLoss

低壓力損耗FasterCycles更快成型周期UniformStockTemperature

均勻儲料溫度StreamlinedMeltFlow

線性熔融流動InjectionMoldingEquipmentMetering計(jì)量Feed進(jìn)料ScrewandCylinderDesign螺桿和料筒設(shè)計(jì)hfhmL/D長徑比=20:1(18:1~24:1)CompressionRatio壓縮比

=2.5:1(2:1~2.5:1)Cylinderbi-metallicforAbrasionResistance雙金屬料筒hmhfTransition過渡LDInjectionMoldingEquipment往復(fù)式螺桿頭結(jié)構(gòu)檢查環(huán)類型:止回環(huán)熔融樹脂流過開放檢查環(huán)檢查環(huán)關(guān)閉,防止在注塑過程中料的回流建議采用止逆閥InjectionMoldingEquipmentStandardCylinderNozzles標(biāo)準(zhǔn)料筒噴嘴HeatingBand加熱環(huán)CylinderBore料筒主體ToMoldProvidesMechanicalandThermalConnectionFromHotCylindertoColderMold提供從熱的料筒到相對冷的模具的機(jī)械和熱連接到模具InjectionMoldingSprueBushing主流道襯套Nozzle噴嘴Radius半徑Orifice主流道孔口段道長度最大5mm射嘴開口:4.76~9.53mm主流道襯套孔口要比噴嘴口徑大0.8~1mm盡可能地短Tooling模具InjectionMoldingtoolingRunnerUseAdequateRunners(FullRound)6to10mm熔體由內(nèi)層向前流動外層接觸模具冷卻固化RunnerFlow流道:平衡的配置是最好的重要點(diǎn)-全圓形或梯形的流道10mm>250mm8mm75-250mm6mm<75mmRunner流道半徑微小的增加就可以很大程度地增加流量,并相應(yīng)地減小壓力降Q=流量

P=壓力降R=澆口半徑N=粘度L=流動距離Q=

8n

LQProportionaltoR4

nR

P4RunnerRunners

Design效率最好較好避免使用PLToolingRunnersSpruePullerREVERSETAPERBESTZPULLERGOODGROOVETROUBLE-SOMESUCKERPINNOTRECOMMENDEDToolingRunnersRESTRICTIVEPREFERREDToolingRunners流動方向冷料井ToolingRunners冷料井流道直徑:D1.5XDUnbalancedSystemAAAABBBBToolingRunnersBalancedSystemAAAAAAAAToolingRunners澆口定位要考慮的基本因素有：制件設(shè)計(jì)、流動和產(chǎn)品最終使用要求。應(yīng)牢記下面的幾點(diǎn)，以此作為一般指南。?需要多澆口的大制件，應(yīng)該有位置足夠緊密的澆口，以減少壓力損失。這樣做可使樹脂流動前緣交匯點(diǎn)的冷卻最小化，從而提供較好的熔合線強(qiáng)度。應(yīng)選擇合適的澆口尺寸，以使樹脂的充填有一個(gè)合理的壓力和速度。?澆口過渡段長度應(yīng)保持盡可能的短。?撞流澆口將有助于保證流入的流體直接對著模腔壁或型芯，從而可以避免漩紋。?為避免夾氣，來自澆口樹脂流，應(yīng)將空氣導(dǎo)向排氣槽。?澆口位置應(yīng)確定好，以便讓樹脂從厚壁部位流向薄壁部位；讓熔合線最小化；并且遠(yuǎn)離沖擊和應(yīng)力區(qū)。?要使漩蚊、放射斑和澆口白暈減至最少，澆口應(yīng)與流道有一個(gè)合適的角度(下圖).?直接澆注到裝飾性表面，會引起表面缺陷。GatedesignGating側(cè)澆口的高度應(yīng)為80~100%的壁厚,寬度應(yīng)為澆口深度的2倍側(cè)澆口0.5mmLandLength1.27~2.53mm900點(diǎn)澆口GatingMoldedPartSpruePartingLine加設(shè)倒圓改善流動KnockOutPinTunnelGateToolingGating3004501mm(min.)R10~25RGateCashewGateToolingGating252.5DVENTINGToolingVentingPartingLineDepth0.035~0.075mmGate2.5mmNoteStep 6mm(min.)0.4~0.75mmToolingVenting25~50mmClearanceAroundKnockout.0025EjectorPinToolingVentingMoldingProcess

成型工藝InjectionMolding使用合適的設(shè)備,正確的條件對材料進(jìn)行預(yù)干燥DryEnvironment-30CdewpointAirFlowRate1cfm/hourlylbofresinusedTemperature120CTime4hrs+InjectionMoldingPredryProcessing工藝Start-up:開機(jī):

PurgewiththeCorrectMaterial

用正確料清洗

UseCorrectProcessingConditions

采用正確加工參數(shù)InjectionMoldingProcessRecommendedPurgeMaterials推薦清洗料Polymer PurgeMaterial聚合物 清洗料Cycolac?/Cycoloy? PMMA,PS,SANNoryl? PS,PMMALexan? PMMA,HDPEValox? PS,HDPEUltem? LEXAN,HDPE(ExtrusionGrade)Supec? HDPEInjectionMoldingProcessInjectionMoldingProcessImportantProcessVariables重要加工參數(shù)MeltTemperature熔融溫度MoldTemperature模具溫度TemperatureProfiles溫度曲線ResidenceTime停留時(shí)間InjectionSpeed注射速度InjectionPressure注射壓力PackPressure保壓ClampTonnage鎖模力Cushion緩沖料墊InjectionMoldingProcessModelofAmorphousPolymersAddingHeatIncreasesSpace外熱提供空間BetweenMolecularChains在分子鏈之間RaiseTemperatureofPolymer

TGLocked固態(tài)EntanglementsStiffFlow難于流動EasierFlow較易流動InjectionMoldingVariablesMeltTemperature熔融溫度35302520151050.030 .060 .090 .120 .150 .180 .210 .240WallThicknessinInches壁厚(In)MeltFlow(in.)LEXAN?101550degF.101@600deg.FIncreasedMeltTemperatureyieldsincreasedFlow.提高熔融溫度導(dǎo)致增加流動However,TooHighaMeltTemperatureMayCauseDegradation.但,過高熔融溫度造成降解InjectionMoldingMaterialThermoplasticsandDegradation熱塑性塑料和降解Degradation降解TemperatureTime時(shí)間Howisheataddedtothepolymer?外熱如何作用于高分子材料ElectricalHeat:電加熱HeaterBands加熱帶MechanicalHeat機(jī)械熱ScrewSpeed螺桿速度BackPressure背壓InjectionPressure/Speed注射速度/壓力Product MeltTemperature(0C)CYCOLAC? 220-260LEXAN? 270-320NORYL? 240-320VALOX? 235-275ULTEM? 340-440CYCOLOY? 240-280XENOY? 240-280SUPEC? 305-330GELOY? 195-220InjectionMoldingProcess產(chǎn)品類別熔體溫度InjectionMoldingBarrelUnitTheReciprocatingScrewScrewRotationFeedsandShearsMaterialIntoaMelt.MeltCollectsIntoFrontofBarrel,ForcingScrewBackShotRotationandBackPressure出量通過螺桿回轉(zhuǎn)，熔體聚集于料筒前部，反作用力使螺桿后退?；剞D(zhuǎn)力矩和背壓15010050255075125150100ScrewDiainmmRPMSCREWSPEEDSuggestions推薦螺桿轉(zhuǎn)速螺桿直徑轉(zhuǎn)速InjectionMolding建議的螺桿轉(zhuǎn)速是根據(jù)直徑而確定的。螺桿的最佳O.D.（外徑）線速度為：每秒8英寸(202.4mm).RPM=[每秒8英寸（202.4mm）的最佳線速度×60]/[螺桿直徑×3.14].例如：螺桿直徑為3英寸（75.9mm）。那么，3(螺桿直徑)×3.1416=9.248,再被每秒8英寸（202.4mm）(最佳線速度)×60來除=51RPM,即為螺桿轉(zhuǎn)速。InjectionMoldingInjectionMoldingEquipmentBarrelUnitTheReciprocatingScrewMeltRequiredtoFillMoldReadyforInjectionShotInjectionPressure注射壓力將要注入模具內(nèi)的熔體InjectionMoldingEquipmentBarrelUnitTheReciprocatingScrewScrewPushesForward:InjectCushionPackingPressure緩沖墊保壓注射InjectionMoldingVariablesInjectionSpeed100010010100 1000 10000LEXAN?141@644degFLEXAN?141@608degFLEXAN?141@572degFApparentViscosity(Pa/s)ShearRate(1/s)InjectionSpeedaffectstheviscosityofthemoltenmaterial.注射速度表觀粘度剪切速率注射速度影響熔體粘度InjectionMoldingVariablesInjectionPressureProfileHydraulicPressureTimeFillTimeScrewRunTimeBackPressurePeakInjectionPressurePressureAppliedbyInjectionRamtoForcethePlasticFromtheBarreltotheMold.注射壓力曲線注射壓力峰值液壓壓力填充時(shí)間MachineDowntime停機(jī)2小時(shí)以下時(shí),建議將料管溫度降低56degC.停機(jī)2~8小時(shí)時(shí),建議將料管溫度降低至170degC.停機(jī)超過8小時(shí)的,建議將料管清洗干凈,且停止加熱.對于玻纖增強(qiáng)樹脂,如果停機(jī)時(shí)間超過30分鐘,應(yīng)將料管清洗干凈.對于含PC的樹脂,不要將料管溫度降至160degC以下Downtime:停機(jī)模溫MoldTempeatureInjectionMoldingProcessInjectionMoldingProcessPartCoolingandSolidificationHotMeltCooledMoldSolidPart制件冷卻和固化熱熔體溫度較低的模具固化的制件MoldTemperature模溫對制件的外觀很重要模溫一致對尺寸控制很重要均勻的模溫可以減少翹曲合理的模溫可以降低產(chǎn)品內(nèi)應(yīng)力合理的模溫可以改善材料流動性InjectionMoldingCooling模溫CoolingsystemMoldCoolingSeriesBubblerINOUTPOORPinBladeINOUT30

CoolingSystemGoodCoolingSystemREGRINDSUGGESTIONSUseOnlyCleanNon-degradedUncontaminatedResinforRegrindKeepItAsNewMaterialNormally20%ofRegrindcanbeUsedScreenSizesshouldbe7to9mmInjectionMoldingRegrind對材料回收使用的建議只使用未降解材料回收料不能有污染要象保存新料一樣通常允許添加20%的回收料過濾網(wǎng)應(yīng)該在7至9MMInjectio